248 COLEOPTERA 



Gr oup 



Maxillary palpi short. Antenna nearly always clavate, inserted at 

 the lateral margins of the forehead, more or less distant from the eyes. 

 Front coxtz cylindrical, transversal, their trochantins distinct ; the poste- 

 rior widened, plate-like at their inner extremity, or throughout their 

 entire length. Abdomen with five segments. Metathoracic parapleura 

 simple. 



Potaminus. 



Sturm.; Lacord. Hist, des Ins. Coleop., Tom. ii.,/. 505. 



Last joint of the maxillary palpi obliquely acuminated, that of the 

 labial obtuse. Antennal club wider and more strongly dented than in 

 Parnus. Prothorax finely margined laterally, without grooves at the 

 sides of its disc ; legs longer ; pro- and meso-sterna notably wider than in 

 that genus. Body clothed with decumbent silky hairs. 



Body oblong. Mentum transversal, widely and deeply hollowed in front. 

 Ligula membraneous laterally, widened and truncated in front. Palpi 

 short, terminal joint of the maxillary longer than the others united. Lab- 

 rum wide, short, hollowed, hiding the mandibles, invisible when the head 

 is retracted, the latter resting on a chin-piece of the prosternum. Eyes 

 oval or rounded, prominent, coarsely facetted. Antenna inserted in 

 transversal furrows situated in front and inner side of the eyes, received 

 when in repose in a groove placed below these organs, with ten or 

 eleven joints ; the first rather large, obconical ; second very large, 

 dilated anteriorly, those following compact, forming a small fusiform 

 club, more or less dented at the inner side. Prothorax transversal, nar- 

 rowed in front, lobed at its base, with its front and hind angles prom- 

 inent, the disc arched. Scutellum moderate, triangular. Elytra more 

 or less elongated. Projecting prosternal and mesosternal processes 

 wide, the first received into a hollow of the second. Legs moderate. 

 Posterior coxae sub-contiguous, abruptly enlarged at the internal side. 

 The four first joints of the tarsi about equal, the fifth shorter than the 

 others taken together. 



The first portion of the description indicates the differences of 

 structure between Potaminus and the genus Parnus of Fabricius, the 

 second gives the characters of the latter genus, as given in Lacordaire's 

 work on the genera of the Coleoptera. 



439. P. angUStiCOlliS, Pascoe; Ann. Mag. Nat. Hist., Feb., 

 1877. P. angusto-ovatus, sat dense griseo-hirtus ; antennis capite fere 

 duplo brevioribus ; prothorace latitudine paulo longiore, apicem versus 

 gradatim angustiore, basi bisinuata, lobo scutellari truncate ; scutello 

 triangulari ; elytris prothorace latioribus, convexis, sat fortiter striato- 

 punctatis ; tibiis intermediis rectis, tarsis linearibus ; unguibus pallidis. 



Long., if lin. 



Waikato. 



Considerably narrower and more convex than P. substriatus. Pro- 

 bably not strictly congeneric. 



